Electronic multiplex to start-stop extensor



Jan. 2, 1951 R SLAYTQN 2,536,578

ELECTRONIC MULTIPLEX T0 START-STOP EXTENSOR Filed Oct. 15, 1948 4Sheets-Sheet l v'Vv WV "M 5 L: Q1}.

J36 Q, 19 a? (g; g; I-

:N ANN-4 FIG. i INVENTOR 24 32 RANSSOM D. SLAYTON BYf wF ATTORNEY Jan.2, 1951 R. D. SLAYTON 2,536,578

ELECTRONIC MULTIPLEX TO START-STOP EXTENSOR Filed Oct. 15, 1948 4Sheets-Sheet 2 INVENTOR RANSOM D. SLAYTON ATTORNEY Jan. 2, 1951 R. D.SLAYTON 2,536,578

ELECTRONIC MULTIPLEX TO START-STOP EXTENSOR Filed Oct. 15, 1948 4Sheets-Sheet 3 I If 38w vvw I a FIG. 3

93 L 89 *7- INVENTOR RANSOM D. SLAYTON ATTORNEY Jan. 2, 1951 R. D.SLAYTON ELECTRONIC MULTIFLEX TO START-STOP EXTENSOR 4 SheetsShee't 4Filed Oct. 15, 1948 Ezmomm INVENTOR RANSOM D. SLAYTQN ATTORNEY PatentedJan. 2, 1951 2,536,578 ii FF i CE ELECTRONIC MULTIPLEX T START-STOPEXTENSOR Ransom D. Slayton, Lombard, Ill., assignor to TeletypeCorporation, Chicago, 111., a corporation of Delaware ApplicationOctober 15, 1948, Serial No. 54,776

9 Claims.

The present invention relates to converters and more particularly to anelectronic converter for transposing multiplex to start-stop telegraphcode signals.

The use of converters for transposing a multiplex to start-stop code isnot new in telegraph practice, it being done in many systems now inoperation. The need for such conversion often ond condition provision ismade for the release of the start-stop oscillator even though a blanksignal been received, which under the above first condition would notrelease the oscillator for operation.

A more complete understanding of the invention may be had by referenceto the following detailed description therecwhen read in conjunctionwith the accompanying drawings, in which:

Figs. 1 to 4, inclusive, illustrate diagrammatically the componentsforming the present invention, and

Fig. 5 illustrates in block diagram the correct positioning of 1 to 4,inclusive, to form an operative apparatus.

Referring to Fig. c, a connector H is provided which is to be connectedto an associated connector in the multiplex receiving distributor apanddeterioration of parts, while mechanical characteristics place a limitto the speed of operation and accuracy of such devices.

Accordingly, an object of the present invention is to provide amultiplex to start-stop converter utilizing electronic devices as muchas possible.

Another object of the invention is to provide an electronic multiplex tostart-stop converter which is low in initial cost and is free from therequirement of repeated adjusting.

Yet another object of the invention is to provide a converter which hasfew mechanical limitations.

A further object of the invention is to provide a converter having noelements operating during a period of failure of the associatedmultiplex circuit.

A further object of the invention is to provide an electronic converterutilizing a start-stop chain distributor controlled by a start-stoposcillator, which wi l not be released for operation except upon thereceipt of a code signal.

Another object of the present invention is to provide a converter whichunder one setting will not be responsive to blank code signals but whichunder a second setting will receive and respond to the reception ofblank code signals.

The converter, in general, comprises a series of selector tubes whichare responsive to the multiplex impulses received by multiplex receivingapparatus, and which operate to store such impulses. A start-stoposcillator is released for operation through means operating in responseto the reception of a code signal to control a startstop distributor ofthe chain type. The electronic distributor operates in conjunction withthe selector tubes to control a plurality of mixer tubes for impressingthe multiplex signals to the startstop line but with the addition ofautomatically inserted start and stop impulses. Under a secpositiveimpulse at this time. may be positioned in one of two positions, but theparatus in conjunction with which the present apparatus is operating.Connected to the connector are five conductors i2 which connect with thereceiving distributor output for the instant channel, such conductorsbeing connected in the well known mechanical multiplex system to thefive receiving segments assigned to the code signal for the instantchannel. The conductors I2 may also be connected to the conductors 1726of the electronic receiving multiplex distributor disclosed incopenoling ap-pication Serial No. 54,772, filed on October 15, 1948, inthe name of T. A. Hansen. If such latter connections are made theconnector M will be connected with the connector 2003 in the citedapplication.

The conductors l2 are connected separately through individual condensersand resistors to the normally negatively biased control grids of aplurality of gas filled selector tubes l3 to H, inclusive. These tubesare of the type which once rendered conducting will continue to conductirrespective of grid bias until an alteration occurs in the anode orcathode circuit thereof. Therefore, as the individual impulses arereceived by the receiving multiplex apparatus and relayed to the instantapparatus over the conductors l2, they will cause the tubes is to H,inclusive, to be rendered conducting or not conducting in accordancewith whether a marking or spacing impulse, respectively, is received.

Upon any of the tubes l3 to ll, inclusive, being rendered conducting,positive potential will be impressed from its output cathode circuitover a branching conductor, such as l8 associated with the tube l3, andthrough a condenser and a varistor or crystal rectifier to a commonconductor i9. The common conductor [9 is connected through a manuallyoperable switch 2| and over a conductor 22 to the normally negativelybiased grid of the normally nonconducting left-hand blank deletercontrol portion of a twin vacuum triode 23. The left-hand portion of thetube 23 will be momentarily rendered conducting by a,

The switch 2| 3 present description will be completed with theassumption being made that it is connected to the conductor 59 as isillustrated. After the dc scription is completed, a furtherdescription-will. be given with the switch 2! in its alternate position.

The anode of the left-hand portion ofthe tubeand over a conductor 28 toa source of positive.

battery. The tube 25 is normally in a conducting condition as willappear hereinafter and therefore through the use of the common anoderesistor 2'? will be extinguished by the left-hand portio'n oi the tubezt 'being rendered conducting. If it is desired to obtain a completedescription of: the known'theory and operationiofthe extinguishment oftubes through the use of commonanode resistors, the same may be had byreference to U. S. Patent No. 2,412,642 issued toWilkerson on-December17, 1946, wherein a complete and detailed description is given Theleft-hand portion of the tube 23 will againbecome momentarily conductingwhenany of the other gas fille'd selector tubes 13 to H, inclusive, arerendered conducting by a. marking impulse occurring in the same codesequence. Tube 25'Will be extinguished by the first marking selection inacode sequence and then. will remain extinguishedregardless of further.conduction or nonconduction by tube 23.

After the complete signal has been received by the receiving multiplexapparatus, which signal consists of five impulse intervals, and suchsignal is stored-inth'e selector tubes-i3 to H, in elusive, a multiplexoperating pulse will beadirected to the instant apparatus through theconmotor I! to a conductor 29. Such multiplex operating pulse mayoriginate from a local segment if a segmented mechanical distributor isutilized, which is used and well known in present practice. However, ifthesystem disclosed in the mentioned T. A. Hansen application isutilizedin conjunction with the present converter with the connector I lconnected to the connector 2003 the conductor 29 will be ccnnected'totheconductor 2006.

The positive multiplexoperating pulse will-be impressed from theconductor 29 to a junction point 35 and thence over a conductor 32 tothenormally negatively biased grid of the start tube 25. renderedconducting.

Upon the tube 25 again being, rendered conducting, positive potentialwill be impressed. from its-output cathode. circuit over aconductor 33and: through a condenser to the normally negatively biased grid of thenormally nonconducting left-hand start pulse amplifier portion of a twinvacuum-triode 3d.- The left-hand pertionof the triodet i will berenderedconducting. I-tmight be noted: that because of thecondenserin'the conductor s-a-a'pulse only will be supplied'to the grid of theleft-hand portion of the-tube 34 and that therefore i such portion willconduct momentarily only;

During the interval of conduction of the lefthand portion of the tube35-, a positive potential impulse will be impressed from-its outputcathe ode'circuitover aconductor 3%:andthrough a suitable condenser andresistor to the moderately negatively; biased control grid of a normallynonconducting: gas filledstart tubettfl causing the latter to. conduct.-The-anode: of: the tube 37 is connected by a common conductor 38. to theSuchimpulse will cause the. tube 25 to be 5 I anodes'of fivegas'filled.distrbutor tubes it to 44, inclusive, and through a common anoderesistor 55 and over a conductor ii to a source of positor: 38 now alsocauses more negative bias to be applied to the control grid of tube 37,preventing the'tube from again being rendered conducting until the.potential of conductor 38 again rises; however, the tube 3? is notrendered nonconducting at this time, but at the time that the tube 'tlilis rendered conducting, as will be described.

Prior to the time that the starttube 37 was rendered conducting,positive potential had been supplied .overtheconductor i? and throughthe common anode resistor 45' to the normally neg.- ati-vely biased gridof the right-hand oscillator controlportion of a twin vacuum-triodeUnderthis condition, with positive bias on the grid of the tube, theright-hand portion thereof is rendered conducting and continues in thatstate until the tube. 3'! isrendered conducting; the potential dropthrough common anode resistor 45 then-removing the positive bias fromthe grid. At the time thatthe right-hand portion of thetubeABisconducting positive potential is impressed from its outputcathode circuit over a conductor ie to the-left-hand portion of astartstop oscillator indicated. generally. by the numeralfii. Nodetailed description of the startstop oscillator nor its operation willbe given at this. time. as thesamemay be had by reference to U. S.PatentNo. 2,373,737, issued on April 17, 1945, to M. Artzt, .whereinacomplete description may be found. Also, the right-hand portion of tube43 has its anode connected to the anode of the left-hand portion of theoscillator 5i and, therefore, whenthe tube 48 conducts its low anodepotential reduces the gain of the oscillator tube.5'l whichwill thus bedoubly; blocked and prevented from operating.

It might .benoted at this time that a normally openmanually operableswitch 52 is connected to ground'and associated with the grid of therighthand portion of the tube 48. If the switch" 52 wereto. be closed,-placingthe grid at ground potential, the right-hand portion of the tube.48 will be rendered nonconducting and the startstoposcillator. 5| willbe released for operation. The distributor would'not operate unless astart impulsewere received from control-tube 26. This allowance of freerunning ofthe oscillator 5| is provided so that the oscillator may becalibrated and adjusted to its desired frequency output. Such afrequencymeasurementmay be madeby applying the continuous Signal to the inputterminals of a cathode-ray osciloscope along with the signalsfrom a.source. ofkno'wnfrequency. A variable. resistor in. the oscillatorcircuit 5! allows frequency adjustment.

Referring again to the fact that the tube 31 was rendered conducting andthe right-hand portion of the tube 38 was rendered nonconducting, nofurther potential will be impressed on the conductor 49 to blockoperation of the start-stop oscillator 51. The oscillator 51 will,therefore, commence to operate with its sine wave output beingdirectedover a conductor 53 to the normally negatively biased grid of theright-hand portion of atwin triode squaring amplifier vacuum tube 54.The twoportions of the tube 54 will operate in a manner well known intheart to direct a square wave. over a conductor 56 to the normallynegatively biased grid of the left-hand amplifier portion ofv a twinvacuum. triode 51 through a condenser 58'. The condenser 58"modifies thetransition points of the square Wave to positive and negative impulseswith the left-hand portion of the tube 51 conducting in response to thepositive impulses. The left-hand portion of the tube 51 will thusamplify a succession of positive pulses which occur in accordance withthe transition points of the sine wave output ofthe oscillator, andwhich will be impressed over a conductor 59 to a junction point 6| andthence over a common conductor 62 to the control grid circuits of thedistributor tubes 40 to 44, inclusive.

During the interval that the start tube 31 is conducting, positivepotential is impressed from its output cathode circuit and throughsuitable resistors over a conductor 63 to the normally well negativelybiased control grid of the distributor tube 40. The tube 40 will not berendered conducting at this time, however, as this potential on itscontrol grid is not suificient to raise the grid to a value allowingconduction. However, this potential will exist during the interval thatthe tube 31 conductors and may be considered as a conditioningpotential. The conditioning potential does not appear instantaneously atthe grid of tube 40, but is delayed by the necessity of charging thegrid condenser through the resistor network.

As it was just mentioned that the start-stop oscillator 5| is releasedfor operation upon the rendering conductive of the tube 31, upon thefirst positive impulse being impressed upon the conductor' 62 from thesquaring tube 54 and the amplifying left-hand portion of the tube 57, anoperating potential will be impressed through a suitable condenser andresistor to the control grids of all of the tubes 40 to 44, inclusive.However, at this time the tube 40 will be the only tube receiving aconditioning potential on its control grid and therefore will be theonly tube of the group which will be rendered conducting. As the tube 40is rendered conducting it extinguishes the tube 31 by means of thecommon anode resistor 46.

The remaining tubes 4| to 44, inclusive, are interconnected with theirpreceding tube in a manner as the tube 40 is connected to the tube 31 sothat at such time as any of the tubes 40 to 43, inclusive, areconducting, they supply conditioning potential to the control grid oftheir associated succeeding tubes M to 44, inclusive. With conditioningpotential being applied to the grid of one of these tubes, thatparticular tube will be rendered conducting upon the receipt of the nextdistributor drive impulse on the conductor 62. The tubes 40 to 44,inclusive, will operate successively as described and thus form anelectronic chain distributor.

It was mentioned previously that the tubes 13 to H, inclusive, were in aconducting or nonconducting state in accordance with the particu arreceived multiplex impulse received therein, the tube being conductingif a marking impulse and nonconducting if a spacing impulse. If it beassumed that marking condition is stored in the selector tube I 3, itwill be conducting and positive potential will be impressed from itsoutput cathode circuit over a conductor 64 to the cathode of theleft-hand mixer portion of a twin vacuum triode 56. If, conversely, itbe assumed that a spacing condition is registered in the tube l3, suchtube will not be conducting and no potential will be impressed on theconductor 64, the oathode of the left-hand portion of the tube 56 thenbeing at ground potential.

During the interval of conduction of the tube 40 positive potential willnot only be impressed from its ouput cathode circuit to the control gridof its succeeding tube 4| but also will be 1m.- pressed over a conductor6'! and through an appropriate resistor to the normally negativelybiased grid of the left-hand portion of the tube 66. Upon such potentialbeing impressed upon the grid, if the No. 1 selector tube !3 isconducting at this time the left-hand portion of the tube 66 will beprevented from being rendered conducting by positive potential beingimpressed on its cathode, or conversely if the tube I3 is not conductingwith no potential being impressed on the conductor 64, the left-handportion of the tube 56 will be rendered conducting.

By reference to Fig. 4, it may be seen that a start-stop receivingdevice or recorder indicated generally by the numeral 68, which may belocated either locally or at a distant point, is connected overconductors {is to the contacts associated with a mechanical line relayindicated generally by the numeral H. The operating winding l2 of theline relay is connected to battery on one side and on the other side tothe anode of the normally conducting right-hand output mixer portion ofthe tube 23. The relay ii is so biased that during the normal conductingcondition of the right-hand portion of the tube 23, a marking or currentcarrying condition will exist on the conductors 69, the battery beingsupplied at the receiver 558. The normal condition of battery or markingon the line is well known, and is utilized in start-stop telegraphy inorder that a recording device may be held in an unoperative conditionduring intervals when no signals are being transmitted over the line.

The grid of the right-hand portion of the tube 23 is connected through aresistor to negative battery, and also by means of a conductor i3connects to the anode of the left-hand portion of the tube 56 and. alsoto the anodes of the left-hand mixer portions of twin vacuum triodes l5,is, H, and i8. Further, the conductor 13 connects to the anode of theright-hand start mixer portion of the tube 34, and thence through acommon anode resistor 19 to a source of positive battery. During theinterval that the right hand portion of the tube 34 and the left-handportions of the tubes 36 and '55 to 13, inclusive, are not conducting,positive potential will be applied-frorn the source or battery throughthe common anode resistor l9 and over the conductor 73 to supplypositive bias to the grid of the right-hand portion of the tube 23. Thisis the normal condition for the various mentioned tubes and allows therelay 1! to be positioned through the conduction of the right-handportion of the tube 23 to supply marking battery to the line conductors69.

It is to be remembered at this time that it was mentioned that with asignal stored in one or more of the selector tubes 13 to H, inclusive,that upon receipt of the multiplex operating pulse over the conductors29 and 32, that the tube 26, the left-hand portion of the tube 34, andthe tube 3'! were all rendered conducting. During the interval ofconduction of the tube 31, which is equal to the start impulse interval,potential will be impressed from its output cathode circuit over aconductor 8| to the normally negatively biased grid of the right-handportion of the tube 34. The right-hand portion of the tube 34 will berendered conducting during this interval which through the use of thecommon anode remomentarily conducting. 'right-handporticn off the tube55 is connected siston l9'iwi'lll'resulti-inra drop: in potential: on

thezconductor"i3..vvithzalresulting rendering noneconducting; ofi the;-right-v-hand: portion. of; the tnh'ew23n At this time the: relay" Tl:through the cessation. of: current in its operatingl 'winding 12 willibeb-iasedior"positionedrto itsopposite conditiomopening. the relaycontacts and resulting in alnoi'current. orrspacing condition onrtheconductors 59, which is indicative of a startcondition: or impulse in:start -stop telegraphy.

Itihas also been: described how after an appropriate' intervali the tube4 ]v will. be rendered conductingwithrthe'extinguishing ofthe tube 31,and the.impressionofipotential to the grid of the leftshan'd: portion ofthe tube 516'. Further, it was described: that the left-hand portion ofthe: tube $61 will: be"; rendered conducting if a spacing; conditionexists for the No. 1 impulse intervalas stored in the selector tube; i3;Ifthe left=hand portion of the tube e3p-is'now rendered conductingrapotential drop will occur on the conductor 3: which is. connected toitsanode anditorthecommon anode resistor 19 whichwill cause a; condition:in the right-hand portion of the tube23 and the relay H similar: to thestart irmiulset condition" described immediately above. Un'den this.condition". a. no current or" spacing conditionawil-lsexist on". theconductors 69;

' Ifiinstead, a marking; condition; exists in the Nozlseiector-tube l3.atthe time that the tube Mb is: conducting" and impressing potentialover thegzconductor 6] to :theigrid of the left-handporfifinflfftubefj.56,.5110111p01l3i011 will beblocked because of: thepositive: potential impressed by the tubes: [3 over; the conductor 54 tothe cathode thereof; Under; this-conditioner potential rise will occur;from thepositivesource' of battery and throughithe common anode resistorE9 to the conductor.- 13'; thereby allowing the right-hand portionzofthertube 23 tobeonceagain rendered conducting. Upon this occurrence therelay H willibe positioned. soas to apply battery or a marking:condition to the conductors 69, similar to thewstop' condition describedinitially.

The tube 49 will remain conducting: for an in- ,tervalequal-to thenormallength of a signal-imlnannerralsosimilclr to that described with respectto: thetube 66.

1e instant: i i lat. the tube ii first conducts, p c potential Will-alsobe impressedfrom its output cathode circuit to a conductor. 32 andthrough a condenser and resistor to the normally negatively biased gridof the right-hand release portionrof the tubefid. This will cause'therighthand" portion of the tube 65 to be rendered The: anode of the by acorzductor et" to the anode of-the tube [3 and thence through a common:anodexresistor 3 and over the conductor: 28 2 to the source of positiveso v of" the right-hand. portion ofthe tubes'ili;

potential; Thus;v upon the :right-handportion; of the tube; fit'beingrendered. momentarily conductinsathe. tube 53 will be extinguished,assuming that: it hadzbeen conducting, through the use ofthe'connnonsanode resistor 85. r

The tube 4 i willremain conducting for; an. in.- terval equal to asignal impulse and thereafter the :tubescfilto d4, inclusive, willconductin'chain fashi'omfor predetermined intervals .as described.During the intervals of conduction oftheetu-bes t? to: id theleftehand'irnixerxportions :of the see lector tubes '58 to '58 Will berendered conduct.- ing or nonconducting in accordance with; the signalcondition stored in the' selectorxtubes; ram iii". Also", during theinterval of conductionof the tubes ii to dd and'inaccordancewit'nWhether thezleft-hand portions of the tubes 75 to 181311?rendered conducting-or not conducting a similar condition will bereflected on the conductor- 13 to control the: right-hand portion of thetube23 and theoutput line relay ii in accordance with priordescriptions. Also at" the instants ofi-conpduction. of. tubes to5%,,the right-hand'release sections of toll Willbe energizedlto ex.-tinguish tubes i to if thelatter had been previously conducting:

At such time as the tube 44 is, rendered conducting, such tube heirsassigned to the:No;, 5 impulse. interval, its output cathodeoircuitrwillI resspotentie through suitable resistors; and

to the: normally negatively biased grid of the left-handstop portion oi"the tube The output pulses from; the start-stop oscillatorwhicii aresquared'and amplified-and impressed on the conductor 59 to the junctionpoint 65 are also impressed; over, a; branching conductor. 33"andlthrough a condenser: and res-iston to the grid of the. left-handportion of. the tube as; Thus, with the grid of theleft-hand porticnof:the tube ii; receiving a conditioning potential from the distributor.tube 44-; upon: the receipt of the next.distributor'drive impulse, thele t handz portion of the tube 48 will be rendered conducting. Thisoperating pulse is received after an interval oiconduction'of the tube tl: sufiicient for the transmission of: the No. 5 signal impulse. Upon.the left-hand portion of the tube 48 being rendered. conducting the"tube id will be extinguished through the use of the common anoderesistor 65.

The left-hand portion of the tube 68 will con.- duct momentarily only asit a vacuum tube and receives but a single impulse through the condenserin the conductor 8? to its grid. However, such interval. of conductionWill be sufiiicient to extinguish the tube M, as mentioned. As theleft-hand portion of. the tube 48 rendered nonconducting, potentialWill. rise on the ccnductor'38. through; the common ,anodejresi'storsuficiently to impress sufiicient: potential on the grid of; the riht-hand portion oi: the tube 43 to allow itto be rendered'conducting.Atthis time potential'isw impressed from its cathode and anode circuitsto block operationof the startstop oscillator described previously;

Also, at such time as'the left-handportionof the-tube iil'is renderednonconducting and a potential rise -exists on the conductor 33 a similarpotential rise will'exist on abranching conductor 38 whichv is connectedthrough a condenser and resistor tov the normallynegatively: biased gridThis will. cause such portion. of thetubetobe; ren dered conducting forthe purpose oijextinguishing the No. 5 impulse selector tube:l1if.:itzhad,b een rendered conducting by the received signal. Threfore,it may be seen that While the righthand release portions of the tubes 3%and E to H, inclusive, are conducting by the associated succeedingdistributor tubes M to 34, inclusive, the right hand portion of the tubein is operated under the control of the rendering nonconducting of theleft-hand portion or the tube 48. Thus, at this time the selector tubes3 to ll, inclusive, will all be in an extinguished condition awaitingoperation in accordance with the next signal that is being received fromthe associated receiving multiplex distributor and impressed over theconductors 52. At this time upon the receipt of a marking impulse in anyimpulse position the apparatus will be re-energized as described. aboveto release the startstop distributor iii and complete another cycle ofoperation.

It might be mentioned. at this time that with the system operating asdescribed above, if a blank signal were to be received from thereceiving multiplex apparatus, which consists of five spacing impulses,none of the tubes i3 to H, inclusive, would be rendered conducting.Under this condition the leit-hand portion of the tube 23 would not berendered conducting and the tube 26 would not be extinguished.Thereafter upon receipt of the next multiplex operating pulse over theconductors 29 and 32 to the control grid of the tube 26, the tube 26would not be rendered conducting as it already is in that condition.Therefore, there would be no positive pulse impressed over its outputconductor 32 and through its condenser to the grid of the left-handportion of the tube 34. The left-hand portion of the tube 34 would notbe rendered conducting which would result in no potential beingimpressed on the conductor 3% and the start tube 3'! would not berendered conducting. With the above condition occurring, the start-stoposcillator 5| will not be released for a cycle of operation and theconverter apparatus will not operate to impress the blank signal on theconductors 69. Therefore, with the apparatus operating as describedabove, no blank signal conditions in the signal initiating means will bepassed to the start-stop receiver 68.

If it now be assumed that the manually operable switch 2| be moved toits right-hand position, the conductor 22 will be connected through theswitch 2| to a conductor 8% which extends to the output cathode circuitof a gas filled sixth pulse selector tube 9|. The normally negativelybiased grid of the tube 93 is connected .through a suitable resistor andcondenser and over a condoctor 92 to the connector 9 i which isconnected to the multiplex receiving apparatus. Such position of theswitch 2| is utilized in schemes of transmission where a sixth pulse isoriginated such as for instance in the transmission of cipher signalswherein the blank start-stop signal combination must be retransmitted.Under this scheme of operation a sixth pulse will be transmittedinvariably from the transmitting apparatus to the receiving multiplexapparatus for each character combination including the blank and willthen be passed over a conductor not shown .to the connector and theconductor 92. Therefore, each time that the sixth pulse is received overthe conductor 92 it will be suflicient to overcome the negative bias onthe control grid of the tube 9| and cause conduction in that tube. Whensuch occurs, positive potential will be impressed from the outputcathode circuit of the tube 9| over the conductor 89, through the thenclosed switch 2|, and over the conductor 22 to the grid of the left-handportion of the tube causing such portion of the tube to be renderedmomentarily conducting. During the prior description of the apparatm itWas mentioned how when the left-hand portion of the tube 23 is renderedconducting, the apparatus will operate to cause the start tube 3? to berendered conducting and the start-stop oscillator 5| to be released fora cycle of operations.

From the above condition it may be seen that the converter apparatus isreleased for a cycle of operation solely under the control of the sixthpulse and not under the control of a marking impulse in one of the fiveimpulse positions. This may be amplified by reference to the switch 2|which no longer connects the conductor 22 to the common conductor i9leading from the output circuits of the selector tubes is to IT,inclusive. Under this setting of the apparatus then it is obvious thatthe release of the converter is under the control of the sixth pulseonly irregardless of the five signal impulses and, therefore, eventhough a blank: signal condition may be received by the selector tubesit to H, inelusive, the apparatus will be released to impress suchcondition to the conductors 53 for recordation at the receiver 88. Asmentioned above the receipt of the sixth pulse is invariable to theconverter apparatus upon the reception or" each char.- acter combinationoriginally presented t the multiplex by distant start-stop transmittingapparatus. It is not received when the channel is idle, or when a speeddifference blank is inserted by the action of the distant transmittingconverter.

It should be remembered at this time that it was stated earlier thatafter the signals had been received in the selector tubes it to H, inclusive. that a multiplex operating pulse would be received at theconnector ii over the conductor 29 and to the junction point 3|. In theevent that the sixth pulse code is being utilized such multiplexoperating pulse will not be received until immediately after both thefive signal impulses and the sixth pulse have been impressed to theconverter apparatus.

The multiplex operating pulse will be impressed from the junction point31 over a conductor 93 to the normally negatively biased grid of theright-hand selector release portion of the tube 51. This portion of thetube will be rendered momentarily conducting at this time. The anode ofthe right-hand portion of the tube 5'5 is connected by means of aconductor 9 to the anode of the sixth pulse selector tube 9% and thencethrough a common anode resistor to a source of positive potential. Thus,upon such time as the right-hand portion of the tube 52" is renderedconducting the sixth pulse selector tube Si will be extinguished.However, the tube 9i will have previously served the purpose ofreleasing the converter apparatus for a cycle of operation andthereafter will be in readiness to respond to the sixth pulse of thesucceeding signal.

While a specific embodiment of the invention has been illustrated anddescribed it is obvious that the invention is not limited to suchdisclosure but that additions and modifications may be made theretowithin the scope and spirit of the invention.

What is claimed is:

1.. In a multiplex to start-stop converter, a start-stop distributor, astart stop oscillator for operating said distributor, a plurality of'tubes, "each of which assigned to cneof the compon'ents of amulti-componentreceived"code signal, said-tubes being renderedconductingin-response toitscomponent being marking, means jointlyresponsivetoone'of saidtubes being rendered conductingand to a multiplexdistributor for rel'easing said oscillator for operation, and means"controlled by said'tubes and said start-stop distribut'or fortransmitting the signal components as stored in said tubes.

2.I'n a multiplex to start-stop converter, a start-stop distributor, astart-stop oscillator for operating said distributor, a plurality oftubes, "each'oi which'isassigned to one of the components of amulti-component received code signal, saidtubes being renderedconducting in response to its component being'marking, means jointlyresponsive to one 01' said tubes being rendered conducting and to amultiplex distributor for releasing said oscillator for operation, and-means controlled by said start-stop distributor for extinguishingconducting ones of said tubes after the signal component stored thereinhas been retransmitted.

'3. In a multiplex to start-stop converter, 2. start-stop distributorcomprising a plurality of tubes, a start-stop oscillator to operate saiddistributor for causing said tubes to be rendered conductingsuccessively, a plurality of tubes for -storing received signalconditions, means jointly responsive to the storing of a signalcondition in saidplurality of storage tubes and to a multiplexdistributor for releasing said oscillator for operation, a plurality ofsecondary tubes each of which is under the joint control of one of saidstorage tubes and one of said distributor tubes, means to -retransmitsignal conditions under the control of said secondary tubes, and meansfor inserting startand stop conditions to said retransmittingmeans-for-retransmission with said signal condi- -ti'ons.

4. In a multiplex to start-stop converter, a start-stop distributor, astart-stop oscillator for operating said distributor, code signalreceiving -means,'a normally conducting tube, means responsive to thereceipt of a code signal by said receiving means for extinguishing saidnormally eonducting tube, means under the control of a 'multiplexdistributor for rendering said extinsguished tube conducting, meanscontrolled by :said tube being again rendered conducting for releasingsaid oscillator for operation, means controlled by said signal receivingmeans and said =tstart-stop distributor for retransmitting the re-"ceived signal conditions, and means for inserting "start and stopconditions to said retransmitting means for retransmission with saidsignal conditions.

5. In a multiplex to start-stop converter, a start-stop distributor, astart-stop oscillator for operating said distributor, multiplex signalcondition receiving means, means for receiving a "sixth code pulse,means under the joint control of the receipt of a sixth code pulse insaid sixth ;pulse receiving means and a multiplex distributor forreleasing said oscillator for operation, means controlled jointly bysaid signal receiving means and said start-stop distributor forretransmitting the multiplex signal conditions, and means for impressingstart and stop conditions onsaid means jointly controlled forretransmitting them with the multiplex signal conditions as start-stopsignals;

12 6. In an'electronic multiplex to start-stop converter, anelectronicdistributor comprising :a pl'u- 'rality of tubes in a series,each ot whichconditions thesucceeding tube, a start-stop oscillator 'tooperate conditioned ones of said tubes successively, multiplex signalreceiving means, --means responsive to the receipt of a signal by saidsignal receiving means and to a multiplex distributor for renderingconducting the first of said tubes in the series and for releasing saidoscillator-for operation, signal utilization means under the jointcontrol of said signal receiving means-and'sai'd distributor tubes, andmeans controlled by the last tube in the series being renderedconducting for shutting ofif operation of said oscillator.

'7. In a multiplex to start-stop converter, a start-stop distributor, astart-stop oscillator for operating said distributor, "a plurality oftubes, each of which is assigned to one ofthe components of amulti-component received codesignal, "said tubes being renderedconducting in=response to its componentbeing marking, means jointly"responsive to one of said tubes being 'rendered "conducting and to amultiplex distributor'forreleasing said oscillator forcperation, meanscontrolled by said tubes and "said start-stop "distributor fortransmitting the signal-components as stored insaid tubesfan'd meansforinserting start and stop conditions to said transmitting means fortransmission with "the signal components.

8. In a multiplex to start-stop vconverter, Ia start-stop distributor, astart-stop oscillatorfor operating said distributor, a plurality oftubes, each of which is-assigned to one of the .components of amulti-component receivdcode signal, said tubes being rendered conductingin'res'ponse to its component being marking, ineansjointly responsive tooneof said tubes'being renderedconducting and to a multiplexdisti'ibutonfor releasing said oscillator for operation, meansjointlyresponsive to the receipt of a contrlpulse anda multiplex distributorfor releasing said oscillator for operation, means for selecting one orthe otherof saidoscillator releasing means for-operation, and meanscontrolledby said tubes and said start-stop distributor-[fortransmitting tliesignal components as stored: in said-tubes.

9.'In a multiplex to .start-stop convertena =start-stop distributor, astartstop ioscillator for operating said distributor, a plurality oftubes, each of which is assigned to one of the components of amulti-componentireceived-inultiplex code signal, means for receivingacontrol pulse, means under the joint control'ioi the receipt of the"control pulse and a multiplex-distributor for releasing :saidoscillator for operation; and means controlled bysaid tubes andsaid-start -stop dis- 'tributor for transmitting the-:signalcomponents 1as :stored insaid tubes.

RANSOM D. SLAYTON.

REFERENCES .CI EED The iollowing refere'nces are :of I record in tlie-file of this patent:

UNITED STATES PATENTS Number Name 7 Date v1 561,526 Vernam -n. '-Nov.17,-1-1925 1,880,906 Duerr .001;. A, 1:932 2,433,362 'I-Iartley r.,-.Dec.-"30, .1947 2,438,492 Bascom= i Mar. 30,-l9l8

